Nova Patents
US6957072B2

Calibration of positioning systems

Summary by NHIP

Mobile Station Calibration

The method calibrates mobile station locations by estimating bias errors without added hardware. It derives position approximations using an n-dimensional bias vector calculated from derivatives of measurement functions and refines positions via a specific covariance equation.

Claim Score by NHIP

Read claim 9, the broadest

Abstract

Mobile station positioning methods are calibrated using an error bias estimation for refining the determination of the mobile station location which does not require any added hardware to the telecommunications system. The position of the mobile station is calculated assuming no bias errors and a first order approximation of the mobile station position is derived as a function of the bias error. The bias error is then estimated and used to refine the previously calculated mobile station position.

US6957072B2, drawing sheet 1
Sheet 1 of 22

Term

Term ended

Expired 23 August 2022, 4.1 years ago.

  1. Priority
  2. Filed
  3. Granted
  4. Expired
  5. Today

16 claims: 2 independent, 14 dependent

  1. 1
    A method of calibrating a mobile station location system in a cellular telecommunications network, the method comprising the steps of:determining a position (z k0 ) of a mobile station in the telecommunications network assuming no bias error;deriving, concurrently, an approximation of the position (z k ) of a k th mobile station as a function of an n-dimensional vector (b) of unknown biases according to a calibration bias estimation equation b = ⁢ b 0 - { ∑ k = 1 N ⁢ H k T ⁢ P k - 1 ⁢ H k - ⁢ ∑ k = 1 N ⁢ ( H k T ⁢ P k - 1 ⁢ G k ⁡ ( G k ⁢ P k - 1 ⁢ G k ) - 1 ⁢ G k T ⁢ P k - 1 ⁢ H k ) } - 1 ⁢ ( ∑ k = 1 N ⁢ H k T ⁢ P k - 1 ⁡ ( Y k - r ⁡ ( z k0 , b 0 ) ) ) wherein b is an updated estimate of b 0 , b 0 is the apriori value of a bias vector, Y k is a generic m-dimensional measurement related to the k th mobile station, z k is the position of the k th mobile station represented by the column vector (xy), H k is a derivative of r(z,b) with respect to bias and G k is a derivative of the function of r(z,b) with respect to position;and refining the position (z k0 ) of the mobile station, using the updated estimate of b, according to the equation Y k =r ( z k ,b )+ e k where k=1, . . . ,N, and e k is an additive noise term with covariance P k .
  2. 9
    Broadest claimClaim Score 12, narrow(NHIP)A system for calibrating a mobile station location system in a cellular telecommunications network, the system comprising:means for determining a position (z k0 ) of a mobile station in the telecommunications network assuming no bias error;means for deriving, concurrently, an approximation of the position (z k ) of a k th mobile station as a function of an n-dimensional vector (b) of unknown biases according to a calibration bias estimation equation b = ⁢ b 0 - { ∑ k = 1 N ⁢ H k T ⁢ P k - 1 ⁢ H k - ⁢ ∑ k = 1 N ⁢ ( H k T ⁢ P k - 1 ⁢ G k ⁡ ( G k ⁢ P k - 1 ⁢ G k ) - 1 ⁢ G k T ⁢ P k - 1 ⁢ H k ) } - 1 ⁢ ( ∑ k = 1 N ⁢ H k T ⁢ P k - 1 ⁡ ( Y k - r ⁡ ( z k0 , b 0 ) ) ) wherein b is an updated estimate of b 0 ,b 0 is the apriori value of a bias vector, Y k is a generic m-dimensional measurement related to the k th mobile station, z k is the position of the k th mobile station represented by the column vector (xy), H k is a derivative of r(z,b) with respect to bias and G k is a derivative of the function of r(z,b) with respect to position;and means for refining the position (z k0 ) of the mobile station using the updated estimate of b, according to the equation Y k =r(z k ,b )+ e k where k=1, . . . ,N, and e k is an additive noise term with covariance P k .
Independent claims2